This disclosure relates to methods for the manufacture of polycarbonate compositions, and the polycarbonate compositions formed thereby. This disclosure also relates to articles comprising the polycarbonate compositions, in particular multilayer thermoplastic films that can be used for in-mold decoration.
Decorating a three-dimensional article via in-mold decoration (IMD), also known as insert mold decoration, involves inserting a decorative film (often referred to as a substrate) into a molding tool; and injecting a molten base polymer behind it in an injection molding cycle. The decorative film is bonded with or encapsulated by the molten base polymer, to provide an injection molded article or finished part having the desired decoration after the injection molding cycle is complete. Thus, the decorative film becomes a permanent fixture of the finished part. The decoration for the finished part can either be exposed to the environment as “first surface decoration” and/or encapsulated between the substrate of the decorative film and the injected material as “second surface decoration.”
The term “decorative film” as used herein refers to a film having surface printing or other marking of an aesthetic, functional, and/or informational nature including, for example, symbols, logos, designs, colored regions, and/or alphanumeric characters. When printed with ink, formable and high temperature inks are generally used. The decorative film can also act as an aesthetic effect carrier and/or as a protective layer for the base polymer, the ink used to mark the film, or both. When used to manufacture a three-dimensional article, decorative films are often thermoformed on a tool into a three-dimensional shape that corresponds to the three-dimensional shape desired for the injection molded article.
Processes for making decorative film are disclosed in U.S. Pat. No. 6,117,384 to Laurin et al., which describes a process wherein a colored decorated film is incorporated with a molten polymer injected behind the film to produce a permanently bonded three-dimensional piece. U.S. Pat. No. 6,458,913 to Honigfort and U.S. Pat. No. 6,682,805 to Lilly also describe insert mold decorative films and articles. Lilly describes a multilayer thermoplastic printable film comprising a thermoplastic film substrate having laminated to one surface a fluoride polymer in order to improve the birefringence and other properties of the film, including chemical resistance.
Polycarbonates are especially useful thermoplastic materials for the manufacture of decorative films, based at least in part on their hardness and processability. Polycarbonate films can also be manufactured to have high transparency, which is advantageous in decorative films.
Despite their wide use, there remains a perceived need in the art for improved polycarbonate compositions for use in the manufacture of decorative films, as well as decorative films with improved properties. For example, there remains a need in the art for polycarbonate compositions and decorative films where the exposed surface of the decorative film has improved scratch and/or chemical resistance.